Patient handling mattresses are known in the art which include at least two flexible material sheets, that together define a plenum chamber, with at least one sheet being perforated with small pinholes over at least a central surface area, and which open up directly to the interior of the plenum chamber. Such prior art mattresses are used by arranging the perforated sheet so that it faces an underlying fixed, generally planar support surface, such as a floor or table. When the mattress is charged with pressurized air, the escape of air under pressure through the pinholes acts initially to jack a load placed upon the mattress above the perforated flexible sheet, and thereby creates an air bearing of relatively small height between the underlying fixed, generally planar support surface and the perforated flexible sheet.
For example, in U.S. Pat. No. 4,517,690, issued to Wegener, an air pallet is disclosed that is formed from upper and lower thin flexible film sheets sealed at their edges to form a plenum chamber. Wegener's air pallet functions to move a load with minimal friction over an underlying generally planar fixed support surface. The bottom thin flexible material sheet is perforated by small diameter perforations such as pin holes at the load imprint area.
In U.S. Pat. No. 5,561,873, issued to Weedling, provides an inflatable flexible pallet within which an array of structurally interrelated inflatable chambers are formed to support a load when inflated. The flexible pallet is configured to resist lateral and longitudinal shrinkage of the load support surface, as well as ballooning and hot dogging. Rotational instability is also reduced by providing a greater load surface support area.
In U.S. Pat. No. 6,073,291, issued to Davis, an inflatable medical patient transfer apparatus is disclosed that has a combination of transverse partition members and a raised perimeter section to reduce deleterious ballooning and uneven inflation as well as quick emergency deflation. Additional differentially inflatable patient rolling chambers are disclosed on the top of the transfer apparatus to provide assistance to medical personnel in beginning to roll patients reclining or lying upon the transfer apparatus, particularly in a deflated condition on a hospital bed.
All of the foregoing devices have suffered from an inability to be cleaned sufficiently and quickly so as to prevent transmission of disease from their patient engaging surfaces after use. Such a mattress would need to have the material contacting the patient be readily washable, and also be non-absorbent, since patients often experience loss of bodily fluids with resultant messing of bed linen and the like.
One solution to this ongoing problem is provided in U.S. Pat. No. 4,627,426, issued to Wegener et al., which discloses a highly absorbent sheet is provided to be placed onto the top of an operating table, and is weakened longitudinally through the center to form paired separable center-joined sections for lateral removal to respective sides of a patient lying on the sheet and centered longitudinally therewith. Thus after surgery, the absorbent pad carrying a significant mass of blood can be quickly removed from the patient by pulling with sufficient force on the opposites sides of the pad, severing the pad along the weakened portion. The pad may have several layers with one or more layers being weakened by thinning the sheet material or perforating the same longitudinally.
Unfortunately, many of the foregoing devices also suffer from the fact that their uninflated area is significantly larger than their inflated area. Consequently, peripheral edge portions of these devices tend to hang over the peripheral edges of a hospital bed or patient transfer cart, adding to the aforementioned cleaning problems. In the medical field, there is a continuing need to easily, safely and comfortably transport an injured person, hospital patient or injured person at the scene of an accident, using an air mattress. There is also a continuing need to be able to easily and safely clean such a mattress after use.